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Lac Megantic disaster: 3D Models of destroyed tanker cars released

Investigators with the Transportation Safety Board have released 3D models of what the destroyed tanker cars look like

Two emergency crew workers speak as they stand in front of a pile of train wheel-set axels inside the red-zone at the site of the explosion in Lac-Mégantic, 370 kilometres southeast of Montreal on Tuesday, July 23, 2013. Photo: Dario Ayala / THE GAZETTE

As car after car of petroleum crude oil exploded in Lac Megantic, burning much of the downtown into nothing, the rubble of the cars themselves lay under a pile of twisted metal and debris.

In the disaster 40 buildings and 50 vehicles were destroyed. Forty-seven people were killed. That was on July 6, 2013, and the investigation is still ongoing.

As part of that investigation, the Transportation Safety Board has created 3D models of what the exploded tankers look like now. The models show weaknesses in the structure of the tanker car, where they were stressed and where the stresses caused the cars to actually rupture. With this data, they can look for patterns in what caused the cars to explode and, hopefully, build newer cars strong enough to resist those stresses.

This is what a scan of a fully functional, normal, standard oil tanker rail car looks like. This is the base for the Transportation Safety Board’s analysis.

The scan of the model car, used as a basis for analysis of the other exploded cars.

One of the challenging parts about protecting these cars from damage is the simple fact that dents in the car reduce the internal volume available for oil. Some of the cars scanned here were so badly damaged that their internal volume shrank by more than 20 per cent. That means all the oil inside somehow had to fit in a much smaller space than designed. Meanwhile, the heat of the fire outside the tankers was causing the oil inside to expand. The oil was trying to take up more space while the space available to it was shrinking. That kind of pressure build-up primes the tanker for an explosion.

These are what the ruptured cars look liked. You can see where they burst open, where they simply bent out of shape, and where they crumpled into pieces.